package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    private class VoucherOrderHandler implements Runnable{
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true){
                try{
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    if (list == null ||list.isEmpty()){
                        continue;
                    }

                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);

                    createVoucherOrder(voucherOrder);

                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e){
                    log.error("处理订单异常",e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList(){
            while (true){
                try{
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    if (list == null ||list.isEmpty()){
                        break;
                    }

                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);

                    createVoucherOrder(voucherOrder);

                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e){
                    log.error("处理pending-list订单异常",e);
                }
            }
        }
    }

    //阻塞队列
    //private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024*1024);
   /* private class VoucherOrderHandler implements Runnable{

        @Override
        public void run() {
            while (true){
                try{
                    VoucherOrder voucherOrder = orderTasks.take();
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e){
                    log.error("处理订单异常",e);
                }
            }
        }
    }*/

    private IVoucherOrderService proxy;

    private void handleVoucherOrder(VoucherOrder voucherOrder){
        Long userId = voucherOrder.getUserId();
        //创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        if (!isLock){
            log.error("不允许重复下单");
            return;
        }
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        long orderId = redisIdWorker.nextId("order");
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.emptyList(), voucherId.toString(), userId.toString(),String.valueOf(orderId));

        int r = result.intValue();
        if (r!=0){
            return Result.fail(r==1?"库存不足":"不允许重复下单");
        }
        //获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        return Result.ok(orderId);
    }



    /**
     * 秒杀下单--lua脚本优化版
     * @param voucherId
     * @return
     */
   /* @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        Long result = stringRedisTemplate.execute(SECKILL_SCRIPT,
                Collections.emptyList(), voucherId.toString(), userId.toString());

        int r = result.intValue();
        if (r!=0){
            return Result.fail(r==1?"库存不足":"不允许重复下单");
        }

        VoucherOrder voucherOrder = new VoucherOrder();
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);

        orderTasks.add(voucherOrder);

        //获取代理对象（事务）
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        return Result.ok(orderId);
    }*/


    /**
     * 秒杀下单
     */
   /* @Override
    public Result seckillVoucher(Long voucherId) {
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);

        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始");
        }

        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经结束");
        }

        if (voucher.getStock() < 1) {
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();
        //synchronized (userId.toString().intern()) {}

        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);

        //获取锁
        boolean isLock = lock.tryLock();
        if (!isLock){
            return Result.fail("不允许重复下单");
        }
        try {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //一人一单
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();

            int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();

            if (count > 0) {
                log.error("该用户已经购买过了");
                return;
            }

            boolean success = seckillVoucherService.update()
                    .setSql("stock = stock - 1")
                    .eq("voucher_id", voucherId).gt("stock", 0)
                    .update();
            if (!success) {
                log.error("库存不足");
                return;
            }

            save(voucherOrder);
    }
}
